Ink Set Dynamic Surface Tension Control for Optical Density and Ooze Suppression

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Solution Overview

Problem

Conventional ink-jet recording technologies fail to sufficiently increase optical density of recorded objects while also suppressing ooze in recorded images, as aggregating agents in treatment liquids do not effectively manage ink viscosity and edge sharpness.

Innovation Solution

An ink set comprising a water-based ink with phosphate group-modified self-dispersing pigments and a treatment liquid containing an aggregating agent, both optimized to maintain specific dynamic surface tensions, enhancing optical density and reducing ooze in recorded images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a treatment liquid containing an aggregating agent is used to increase optical density, then the optical density of the recorded object increases, but ooze in the recorded image is not suppressed sufficiently

Engineering Contradiction:
Improveoptical densityVSAvoidooze in recorded image
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the dynamic surface tension of both the water-based ink (35-45 mN/m at 50 ms) and the treatment liquid (33-45 mN/m at 50 ms). This parameter optimization enables the aggregating agent to effectively increase optical density while the controlled surface tension prevents excessive spreading and ooze in the recorded image

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining phosphate group-modified self-dispersing pigment in the water-based ink with an aggregating agent in the treatment liquid. This composite approach allows the pigment particles to aggregate effectively upon contact with the treatment liquid, achieving high optical density while maintaining image sharpness through the specific surface tension characteristics

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If an aggregating agent is used to increase optical density, then pigment aggregation occurs, but control over ink viscosity and edge sharpness deteriorates

Engineering Contradiction:
Improveoptical densityVSAvoidink viscosity control
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent employs parameter changes by optimizing the dynamic surface tension values of both the ink and treatment liquid within specific ranges (35-45 mN/m and 33-45 mN/m respectively). This parameter control ensures that the aggregating agent functions effectively to increase optical density while maintaining proper viscosity control and preventing excessive spreading that would compromise edge sharpness

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The ink set effectively increases optical density and suppresses ooze in recorded images by using phosphate group-modified self-dispersing pigments and adjusting dynamic surface tensions, resulting in improved ink stability and edge sharpness.

Implementation Method 1

The aggregating agent contained in the treatment liquid can cause a self-dispersing pigment in a water-based ink to aggregate, resulting in increasing an optical density (an OD value) of the recorded object

Methodology Applied
Scientific EffectAggregation: Coagulation

Implementation Method 2

A dynamic surface tension of the water-based ink, measured under the condition where a life time is 50 ms, is in the range of 35 mN/m to 45 mN/m. A dynamic surface tension of the treatment liquid, measured under the condition where a life time is 50 ms, is in the range of 33 mN/m to 45 mN/m

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2390286B1Ink set and ink-jet recording method
Publication Date: 2017.07.26 BROTHER KOGYO KK
  • EP2390286B1 patent drawingFigure 1
  • EP2390286B1 patent drawingFigure 2A~2B
  • EP2390286B1 patent drawing

AI summary

An ink set containing a water-based ink for ink jet recording and a treatment liquid. The water-based ink contains a phosphate-group modified self-dispersing pigment, water, and a water-soluble organic solvent. The treatment liquid contains an aggregating agent, water, and a water-soluble organic solvent. A dynamic surface tension of the water-based ink measured under the condition where a life time is about 50 ms, is in the range of 35 mN/m to 45 mN/m. A dynamic surface tension of the treatment liquid, measured under the condition where a life time is about 50 ms, is in the range of 33 mN/m to 45 mN/m.